For exemplary purposes, the unique oil flinger of the present invention will be described in association with a scroll machine. It is to be understood that it is within the scope of the present invention to utilize the unique oil flinger of the present invention with any device having a rotating shaft.
A class of machines exists in the art known as “scroll” machines for the displacement of various types of fluids. Such machines may be configured as an expander, a displacement engine, a pump, a compressor, etc., and the features of the present invention are applicable to any of these machines. For purposes of illustration, however, the disclosed embodiments are in the form of a hermetic refrigerant compressor.
The concept of a scroll compressor has been known for some time and it has been recognized as having distinct advantages. For example, scroll compressors have high isentropic and volumetric efficiency, and, hence, are relatively small and light weight for a given capacity. They are quieter and more vibration free than many compressors because they do not use large reciprocating parts (e.g., pistons, connecting rods, etc.) and because all fluid flow is in one direction with simultaneous compression in plural opposed pockets, there are less pressure-created vibrations. Scroll compressors also tend to have high reliability and durability because of the relatively few moving parts utilized and the relatively low velocity of movement between the scrolls. Scroll compressors which have axial and radial compliance to allow fluid leakage have an inherent forgiveness to fluid contamination.
Generally speaking, a scroll compressor comprises two spiral scroll wraps of similar configuration, each mounted on a separate end plate to define a pair of scroll members. The two scroll members are interfitted together with one of the scroll wraps being rotationally displaced 180° from the other. The compressor operates by orbiting one scroll member (the orbiting scroll member) with respect to the other scroll member (the fixed scroll member or the non-orbiting scroll member) to make moving line contacts between the flanks of the respective wraps, defining moving isolated crescent-shaped pockets of fluid. The spiral scroll wraps are commonly formed as involutes of a circle, and ideally there is no relative rotation between the scroll members during operation, i.e. the motion is purely curvilinear translation (i.e. no rotation of any line on the body). The fluid pockets carry the fluid to be handed from a suction zone located at the outer periphery of the scroll compressor where a fluid inlet is provided to a discharge zone located centrally in the scroll compressor where a fluid outlet is provided. The volume of a sealed pocket is continuously reduced as it moves from the suction zone to the discharge zone. At any one instant of time, there will be at least one pair of sealed pockets and where there are several pairs of sealed pockets at one time, each pair will have a different volume from the other pairs.
Two types of contacts define the fluid pockets formed between the scroll members. First, axially extending tangential line contacts are formed between the spiral wrap faces or flanks of the wraps caused by radial forces (flank sealing) and second, area contacts (tip sealing) caused by axial forces are formed between the plane edge surfaces (tips) of each wrap and the opposite end plate. For high efficiency, good sealing must be achieved for both types of contacts.
While scroll compressors have relatively few moving parts, lubrication for these moving parts is a necessity for the durability of the scroll compressor. In a low-side compressor, a portion of the lubrication is suction gas flow which is allowed to pick up the overspray of lubricant from the moving components of the compressor and circulate the lubricant throughout the compressor. Suction gas is baffled and routed through the compressor in such a way as to control the amount of lubricant that is picked up by the suction gas to a tolerable level for compressor operation at rated operating conditions. The lubricant which is picked up by the suction gas primarily lubricates the two contacts which define the fluid pockets (flank sealing and tip sealing).
The lubricant that is supplied to the other moving components and thus the sprayed lubricant that is picked up by the suction gas is supplied by a lubricant supply system which utilizes a lubricant sump located in the lower or bottom portion of the shell. The drive shaft extends into the sump to pump lubricant through a bore extending through the drive shaft to all of the various moving components of the compressor which require lubrication. Typically a lubricant flinger is disposed within the bore of the drive shaft and the bottom of the drive shaft rests on a thrust washer secured to the bearing housing rotatably supporting the drive shaft. The thrust washer includes a hole for the lubricant which is smaller than the bore supporting the lubricant flinger. The lubricant flinger and the thrust washer together as an assembly make up the lubricant pump which pumps the lubricant through the bore in the drive shaft to the moving components requiring lubrication.
While the above designed lubricant pump works well when the drive shaft is supported by the thrust washer, a problem arises when the design for the compressor supports the drive shaft in a different manner and thus, the thrust washer is not available as a component of the lubricant pump. While it may be possible to supply the thrust washer and its associated retention components solely for the purpose of creating the lubricant pump, this option is costly in both additional components as well as additional machining to accommodate these additional components.
The continued development of scroll compressors in general and lubrication systems in particular have been directed towards the design and simplification for the lubricant pump for the lubrication system.